Speculation into what future versions of Dragon will involve

[sanman]

Does anyone know of any sketches/photos/renderings of what this Dragon 2.0 is supposed to look like? When you say "cool looking" - in what way? What does it look like? I tried Googling, but couldn't find anything.

[Elmar Moelzer]

Does anyone know of any sketches/photos/renderings of what this Dragon 2.0 is supposed to look like? When you say "cool looking" - in what way? What does it look like? I tried Googling, but couldn't find anything.

No, IIRC Musk wanted to keep it under wraps until some time next year, but I might be remembering this wrong.

[douglas100]

I agree with Lars there. Certainly a good point.

Yes indeed. Soyuz has a steeper sidewall and this is what the most recent one looked like after landing: http://spaceflight.nasa.gov/gallery/images/station/crew-33/hires/201211190015hq.jpg

SpaceX were trading interior volume versus sidewall angle when they designed Dragon. My amateur guess is that they will essentially keep the same mold line for the new version.

[CuddlyRocket]

But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

I assume that any change of shape wouldn't be for aesthetic reasons but for engineering ones. The only drivers I can think of are to increase the internal volume; reduce mass for a given volume; reduce the cost of manufacture or to improve the effectiveness of the SuperDracos by reducing the cosine losses. Are there any others?

Noting Lars_J's point about the re-entry angle etc, would it be possible for the capsule to be asymmetric with the 'front side' sidewall at a steeper angle? Can an asymmetric shape nonetheless have symmetric aerodynamic loads? Could the fact that the SuperDracos are not at 90 degrees have anything to do with this?

I note that the Orion is planned to have almost twice the internal pressurised volume as the current Dragon. Elon might want to close the gap if possible; somewhat at least. Another way to increase volume would to make the diameter of the base wider (though this doesn't change the shape). Although the F91.1 and FH have the same diameter as the F1.0, the trunk could be flared to match the two (the current design of the Orion SM seems to do something similar). Payload fairing often have greater diameters than their launchers, so this wouldn't seem to present any particular problems?

[douglas100]

But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Having the SuperDracos mounted in the sidewalls will certainly make it look different. They may be mounted in pods which protrude further than the version we've seen already. So in that sense, the mold line would be a bit different. To redesign the basic shape would be close to developing a completely new vehicle and I think it would be too costly. I very much doubt the basic shape of the new vehicle will be asymmetrical.

As far as Musk's remarks are concerned, What he means by "cool" and "futuristic" in this context is anyone's guess. That's for the Kremlinologists. 

[meekGee]

Especially in light of the requirement for reusability, I think the major driver is reducing of the cosine losses on the SDs, which would mean, at a minimum, sticking them out further.

As for changing the vessel shape, I don't see the clear driver for it, but I also don't see why that's so difficult. Seems like development wise, the vessel never was the most difficult item - this goes back to vertical integration - SpaceX's idea of "small changes" is quite different than that of other companies...

Just from what we know, the SD pods are already changing the external shape so that CFD work has to be re-done.  Load paths are affected by the SDs of course. Placement of components around the vehicle - same.  Life support etc - new.  Docking mechanism - new.   So really, why does changing the pressure vessel shape suddenly takes us to a "new level of change"? 

[Hooperball]

@CuddlyRocket,

Another driver is landing legs.

From a weight saving stand point it seems logical that these legs would be integral with super draco structural mounts.

From a simplicity stand point, IF the super dracos are housed in pods to improve cosine losses, legs that are fixed to or deployable from these pods would save the hassle of having to pierce the heat shield with legs to land.

S

[IRobot]

A "perfect" capsule would have a larger top, to reduce cosine losses for the super dracos, to increase volume and to include landing gear, but that would require some kind of inflatable shield, but those are not yet proven tech...

[cambrianera]

A question to the people that believes that Dragon 2.0 will be similar to cargo Dragon: where is SpaceX going to fit SuperDracos?
Some models seen on displays or in artworks seems incompatible with dragon pressure vessel.

[Lars_J]

A question to the people that believes that Dragon 2.0 will be similar to cargo Dragon: where is SpaceX going to fit SuperDracos?
Some models seen on displays or in artworks seems incompatible with dragon pressure vessel.

No, look closer, it is compatible. (both that display model and the rendering you attached are at least) Notice the raised areas around the thrusters. The SD's would be mounted on the outside of the pressure vessel, and the raised area/fairing would protect them during ascent.

[Lars_J]

But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Oh c'mon. "futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think:  http://en.wikipedia.org/wiki/Occam's_razor

[Jason1701]

A question to the people that believes that Dragon 2.0 will be similar to cargo Dragon: where is SpaceX going to fit SuperDracos?
Some models seen on displays or in artworks seems incompatible with dragon pressure vessel.

No, look closer, it is compatible. (both that display model and the rendering you attached are at least) Notice the raised areas around the thrusters. The SD's would be mounted on the outside of the pressure vessel, and the raised area/fairing would protect them during ascent.

The basic concept is compatible, but I think (and believe Elon has been implying) that the fairings will need to be much bigger.

[meekGee]

But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Oh c'mon. "futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think:  http://en.wikipedia.org/wiki/Occam's_razor

Lars, Occam's razor says that a simpler explanation to a given observation is *most likely* to be correct.

We don't have an observation, and we don't have competing explanations...

We are guessing how many changes will be in Dragon 2.0 vs Dragon 1.0.

Given all that IS changing, I am not sure that a new pressure vessel is such a big deal (why would it be?).  I do agree that it is not at the top of the priority list for them, but we'll have to wait till we have more info.

Until more information is available, this thread is going to be re-hashing arguments....

[Elmar Moelzer]

Well from what I understand Elon said that the SDs will move away from the "bottom side" of the capsile. That could still mean two symetry axis (as in a sketch I posted earlier). It could also mean that it will only have one symetry axis with two pairs of superdracos firing at a really odd angle.

[beancounter]

But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Oh c'mon. "futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think:  http://en.wikipedia.org/wiki/Occam's_razor

Lars, Occam's razor says that a simpler explanation to a given observation is *most likely* to be correct.

We don't have an observation, and we don't have competing explanations...

We are guessing how many changes will be in Dragon 2.0 vs Dragon 1.0.

Given all that IS changing, I am not sure that a new pressure vessel is such a big deal (why would it be?).  I do agree that it is not at the top of the priority list for them, but we'll have to wait till we have more info.

Until more information is available, this thread is going to be re-hashing arguments....

Is Dragon2 really what Elon is talking about?  Is it Dragon for crew under CiCap or is it something further out say for Mars or BEO?  I don't know but it's fun reading what others think.

[Lars_J]

But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Oh c'mon. "futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think:  http://en.wikipedia.org/wiki/Occam's_razor

Lars, Occam's razor says that a simpler explanation to a given observation is *most likely* to be correct.

We don't have an observation, and we don't have competing explanations...

Yes we do. If you haven't seen it, you should read the thread again.
- Option A: Dragon 2 is simply CCICAP crew Dragon, minimal changes - Musk is exaggerating.
- Option B: Dragon 2 is completely different, all kinds of futuristic, looks very different than the current Dragon. It could be bigger, a completely different shape.

Hmmmm... Which one is more likely. ::8

[meekGee]

But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Oh c'mon. "futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think:  http://en.wikipedia.org/wiki/Occam's_razor

Lars, Occam's razor says that a simpler explanation to a given observation is *most likely* to be correct.

We don't have an observation, and we don't have competing explanations...

Yes we do. If you haven't seen it, you should read the thread again.
- Option A: Dragon 2 is simply CCICAP crew Dragon, minimal changes - Musk is exaggerating.
- Option B: Dragon 2 is completely different, all kinds of futuristic, looks very different than the current Dragon. It could be bigger, a completely different shape.

Hmmmm... Which one is more likely. ::8

Those are not too explanations of some observation...   Those are speculations trying to interpret what Elon might have meant and guess what he might have hidden in his garage...  They don't explain anything.

Anyway, semantics aside - nobody answered why changing the pressure vessel is such a big deal.

Everyone agrees that the outer mold line is new because the SDs are now sticking out a lot, thus re-entry dynamics are new, obviously the SD systems (LAS, landing) are new, the regular Draco motors probably moved to accommodate the SDs and maybe there are fewer of them, there's new life support systems, new docking mechanism. 

At this point - what exactly do you mean by "small change" ?    I actually don't see how keeping it unchanged saves much.

Once we realize the cargo Dragon can't "just have SD attached to it", then it's a new vehicle.  They didn't call it v1.1 or v1.5.  They called it 2.0, and I think this means that went back and designed it from scratch.  And that effort could have started a lot earlier than you think, even before the first Dragon flew.   You learn a lot by building an iteration of hardware even before you actually test it out.

To me, btw, a "large change" would be if some of the launch delta-V would be moved to the Dragon.  Now that there's major thrust capability to it, I don't see why SII won't cut out 1 km/sec early.  (I wonder where it will reenter if they do that...)

[ArbitraryConstant]

Now that there's major thrust capability to it, I don't see why SII won't cut out 1 km/sec early.  (I wonder where it will reenter if they do that...)

Because the SpaceX abort system uses propellant needed for orbital maneuvering and the only reason that's a win is because if you abort you're about to parachute into the ocean and don't need the propellant. If you need bigtime delta-v, you're better off using a pump fed engine with higher ISP propellants, no cosine losses, and a proper vac nozzle. Exactly the second stage they already have, in other words.

[Lars_J]

They didn't call it v1.1 or v1.5.  They called it 2.0, and I think this means that went back and designed it from scratch.

Sigh... In other words, you ignore what evidence is out there (CCiCap, statements by informed people like Jim) and decide to make stuff up. Well, prepare to be disappointed.

And BTW, since you seem to care so much about determining meaning in numerology - I believe Musk called in "Dragon 2", not "Dragon 2.0". There is a fine difference there, if you care to see it.

[CuddlyRocket]

..."futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think...

But the simplest explanation of what Elon means when he says the Dragon 2 will look different to the existing Dragon and 'futuristic' is that it will look different to and futuristic etc. Any other explanation gets you into conspiracy theories about why Elon is saying something not true.

It might be a correct conspiracy theory of course , as real life often doesn't follow Occam's Razor, but I'm not seeking to divine truth and falsehood here. All I'm asking and considering is if the Dragon 2 looks different etc, how and why might that be true. This is a discussion board after all, not an arbitration service! The truth will out in due course - no later than the test of the LAS, and probably earlier.

I think the point is well made that given all the other changes necessitated by the incorporation of SuperDracos and landing legs etc, that a fundamental redesign might not introduce that much more time and expense. Also, there may well be problems with the Dragon and/or its manufacture that SpaceX has not divulged but which it might want to correct.

One other possible driver for a change is Elon's comment that the Dragon 2 could be used to land on any other Solar System body with a solid or liquid surface. Any there any changes that might make it more effective for such purposes; that might make it a more effective deployer of scientific instrument packages or even act as a launch pad for a sample return, for instance?

Of course the priority for the design is to come up with a safe, effective and cost efficient LEO/ISS crew vehicle!